The present invention is directed to polyolefin composite materials and methods for producing the same. More specifically, this invention relates to polyolefin composite materials containing a metallic layer that are useful as flooring underlayments for laminate floors, and methods for producing the same.
Laminate floors are relatively new flooring materials that may be used in place of more traditional materials, such as wood, tile, or vinyl, but are typically constructed to resemble either wood or tile. Laminate floors generally comprise two or more layers, including a top or surface layer and a core layer. The surface layer is a protective, wear-resistant layer which may contain aluminum oxide particles or other materials that form a hard, durable surface. The core layer to which the surface layer is bonded may comprise high density fiberboard. This wood-based material may include a tongue-and-groove design to allow pieces of the flooring to be bonded together with an adhesive. The laminate may also include a bottom layer to help balance the flooring and add strength.
Laminate floors are commercially available from various manufacturers in the flooring business, and are designed to be installed as a floating floor, i.e., not nailed or glued to the subfloor. Instead, the flooring is applied over a floor xe2x80x9cunderlayment,xe2x80x9d which is typically a thin layer of polyethylene foam (e.g., less than 0.1 inch), to provide cushioning and sound reduction. When laminate flooring is applied on a concrete sub-floor, it is important that the underlayment also provide a barrier to the passage of water vapor therethrough so that water vapor from the concrete subfloor does not cause the core/fiberboard layer of the laminate floor to deteriorate from rotting. While polyethylene (PE) foam provides cushioning and sound reduction, it is an inadequate barrier to the passage of water vapor as shown by its high water vapor transmission rates (WVTR). Further, while many laminate flooring materials include a bottom layer, this layer generally does not provide a barrier to the passage of water vapor.
It has previously been proposed to adhere a sheet of polyethylene film to a sheet of polyethylene foam in order to provide a composite structure having a lower WVTR than a sheet of polyethylene foam alone. Although WVTRs of about 0.6 grams/100 in2 per 24 hours (measured at 100xc2x0 F. and 90% relative humidity) or less can be obtained using polyethylene foam/film composites, there is a continued need for floor underlayments having even lower WVTRs. In addition, it would be desirable to achieve lower WVTRs with thinner films, thereby using less resin to make the film and, as a result, reducing the cost of the floor underlayment composite.
Further, conventional polyethylene foam/film underlayments are torn and punctured too easily in the tough building construction environments where they are utilized, thereby compromising the integrity of the water vapor barrier that the PE film is otherwise intended to provide. Underlayments composites with increased tensile strength and tear initiation resistance of the film component of conventional underlayment composites would have a beneficial impact on the abuse- and tear-resistance of the underlayment material.
In light of the foregoing, there is a continued need in the art for improved composite materials that are useful as flooring underlayments for laminate floors and methods for making the same. The composite materials should provide a combination of good vapor barrier and mechanical properties. The composite materials should also be economical to manufacture. In addition, the composite materials should provide good acoustic and thermal insulation properties.
The present invention provides composite materials that are useful as flooring underlayments, and methods of producing the same. The composite materials of the present invention provide improved moisture barrier properties, such as very low water vapor transmission rates, as compared to conventional composite materials. The composite materials of the present invention also provide good acoustic and thermal insulation properties as compared to conventional composites. In addition, the composite materials of the present invention have improved mechanical properties, including tensile strength, reflectivity, and emissivity.
In one of its aspects, the present invention relates to composite materials having a film operatively associated with a polyolefin foam layer and at least one metallic layer operatively associated with at least one of the foam layer and the film. In one embodiment, the metallic layer is a metallized film. In another embodiment, the metallic layer is a foil laminate. The foil laminate optionally has a multilayer structure. The metallic layer is optionally coated with a corrosion resistant coating. The metallic layer can also contain one or more corrosion resistant additives. The metallic layer can be positioned generally adjacent to the foam layer and/or the film. In particular, the metallic layer can be heat laminated or bonded to either one or both of the foam layer and the film.
In another of its aspects, the present invention relates a composite flooring materials having a first film adhered to a first surface of a foam layer, a second film adhered to a second surface of the foam layer, and a metallic layer operatively associated with at least one of the foam layer, the first film, and the second film.
In still another of its aspects, the present invention relates to composite flooring materials having a metallic layer operatively associated with a foam layer. At least one edge of the metallic layer extends beyond a corresponding edge of the foam layer. In one embodiment, the metallic layer is coated with a corrosion resistant coating. In another embodiment, the metallic layer contains one or more corrosion resistant additives.
In still another of its aspects, the present invention relates to methods for making composite materials wherein a film is operatively associated with a surface of a foam layer such that at least one edge of the film extends beyond a corresponding edge of the foam layer. A metallic layer is operatively associated with at least one of the film and the foam layer. The metallic layer can be positioned generally adjacent to the foam layer and/or the film. In particular, the metallic layer can be heat laminated or bonded to either one or both of the foam layer and the film.